Directional controllers of machines have traditionally included an operator interface or switch assembly connected to the transmission of the machine through a mechanical linkage. Specifically, a shift lever, or other similar device, is pivotally mounted to a base and is movable through one of various gear positions, such as forward, neutral, and reverse. More recently, however, contact type switches are being used to detect the selected gear position and use this position information to electronically facilitate a change in gear position via commands from an electronic controller.
In either arrangement, contact type switches are typically employed to detect the selected gear position of the shift lever and transmit the information to a controller of the machine. The controller of the machine may use this information for various purposes and may transmit the information to various subsystems of the machine. Contact switches, however, require physical contact to produce an electrical signal. Unfortunately, the contacts on these switches may become corroded or worn with use or, alternatively, the contacts may no longer form an acceptable electrical connection after repetitive use. Replacing such switches may be difficult and expensive, and may also require a significant period of downtime for the machine.
In order to avoid the problems associated with contact type switches, switches have been developed that incorporate contactless sensors. Hall effect switches are well known contactless switches, especially in the position and motion sensing fields, for providing improved life expectancy compared to the traditional, contact type switch assemblies. As shown in U.S. Pat. No. 6,550,351, a driver interface in the form of a shift lever is provided. The position of the shift lever is sensed using a plurality of discrete position Hall effect sensors and a rotational position Hall effect sensor. The output of the sensors is directed to an electronic control module, which determines the selected position and energizes a transmission actuator to change a gear position of the transmission. This reference, however, does not contemplate a sensor configuration that remains robustly reliable in the presence of electromagnetic interference.
The present disclosure is directed to one or more of the problems set forth above.